/*

 * wrppm.c

 *

 * Copyright (C) 1991-1994, Thomas G. Lane.

 * This file is part of the Independent JPEG Group's software.

 * For conditions of distribution and use, see the accompanying README file.

 *

 * This file contains routines to write output images in PPM/PGM format.

 * The extended 2-byte-per-sample raw PPM/PGM formats are supported.

 * The PBMPLUS library is NOT required to compile this software

 * (but it is highly useful as a set of PPM image manipulation programs).

 *

 * These routines may need modification for non-Unix environments or

 * specialized applications.  As they stand, they assume output to

 * an ordinary stdio stream.

 */



#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */



#ifdef PPM_SUPPORTED





/*

 * For 12-bit JPEG data, we either downscale the values to 8 bits

 * (to write standard byte-per-sample PPM/PGM files), or output

 * nonstandard word-per-sample PPM/PGM files.  Downscaling is done

 * if PPM_NORAWWORD is defined (this can be done in the Makefile

 * or in jconfig.h).

 * (When the core library supports data precision reduction, a cleaner

 * implementation will be to ask for that instead.)

 */



#if BITS_IN_JSAMPLE == 8

#define PUTPPMSAMPLE(ptr,v)  *ptr++ = (char) (v)

#define BYTESPERSAMPLE 1

#define PPM_MAXVAL 255

#else

#ifdef PPM_NORAWWORD

#define PUTPPMSAMPLE(ptr,v)  *ptr++ = (char) ((v) >> (BITS_IN_JSAMPLE-8))

#define BYTESPERSAMPLE 1

#define PPM_MAXVAL 255

#else

/* The word-per-sample format always puts the LSB first. */

#define PUTPPMSAMPLE(ptr,v)			\

	{ register int val_ = v;		\

	  *ptr++ = (char) (val_ & 0xFF);	\

	  *ptr++ = (char) ((val_ >> 8) & 0xFF);	\

	}

#define BYTESPERSAMPLE 2

#define PPM_MAXVAL ((1<<BITS_IN_JSAMPLE)-1)

#endif

#endif





/*

 * When JSAMPLE is the same size as char, we can just fwrite() the

 * decompressed data to the PPM or PGM file.  On PCs, in order to make this

 * work the output buffer must be allocated in near data space, because we are

 * assuming small-data memory model wherein fwrite() can't reach far memory.

 * If you need to process very wide images on a PC, you might have to compile

 * in large-memory model, or else replace fwrite() with a putc() loop ---

 * which will be much slower.

 */





/* Private version of data destination object */



typedef struct {

  struct djpeg_dest_struct pub;	/* public fields */



  /* Usually these two pointers point to the same place: */

  char *iobuffer;		/* fwrite's I/O buffer */

  JSAMPROW pixrow;		/* decompressor output buffer */

  size_t buffer_width;		/* width of I/O buffer */

  JDIMENSION samples_per_row;	/* JSAMPLEs per output row */

} ppm_dest_struct;



typedef ppm_dest_struct * ppm_dest_ptr;





/*

 * Write some pixel data.

 * In this module rows_supplied will always be 1.

 *

 * put_pixel_rows handles the "normal" 8-bit case where the decompressor

 * output buffer is physically the same as the fwrite buffer.

 */



METHODDEF void

put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,

		JDIMENSION rows_supplied)

{

  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;



  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);

}





/*

 * This code is used when we have to copy the data and apply a pixel

 * format translation.  Typically this only happens in 12-bit mode.

 */



METHODDEF void

copy_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,

		 JDIMENSION rows_supplied)

{

  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;

  register char * bufferptr;

  register JSAMPROW ptr;

  register JDIMENSION col;



  ptr = dest->pub.buffer[0];

  bufferptr = dest->iobuffer;

  for (col = dest->samples_per_row; col > 0; col--) {

    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(*ptr++));

  }

  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);

}





/*

 * Write some pixel data when color quantization is in effect.

 * We have to demap the color index values to straight data.

 */



METHODDEF void

put_demapped_rgb (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,

		  JDIMENSION rows_supplied)

{

  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;

  register char * bufferptr;

  register int pixval;

  register JSAMPROW ptr;

  register JSAMPROW color_map0 = cinfo->colormap[0];

  register JSAMPROW color_map1 = cinfo->colormap[1];

  register JSAMPROW color_map2 = cinfo->colormap[2];

  register JDIMENSION col;



  ptr = dest->pub.buffer[0];

  bufferptr = dest->iobuffer;

  for (col = cinfo->output_width; col > 0; col--) {

    pixval = GETJSAMPLE(*ptr++);

    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map0[pixval]));

    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map1[pixval]));

    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map2[pixval]));

  }

  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);

}





METHODDEF void

put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,

		   JDIMENSION rows_supplied)

{

  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;

  register char * bufferptr;

  register JSAMPROW ptr;

  register JSAMPROW color_map = cinfo->colormap[0];

  register JDIMENSION col;



  ptr = dest->pub.buffer[0];

  bufferptr = dest->iobuffer;

  for (col = cinfo->output_width; col > 0; col--) {

    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map[GETJSAMPLE(*ptr++)]));

  }

  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);

}





/*

 * Startup: write the file header.

 */



METHODDEF void

start_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)

{

  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;



  /* Emit file header */

  switch (cinfo->out_color_space) {

  case JCS_GRAYSCALE:

    /* emit header for raw PGM format */

    fprintf(dest->pub.output_file, "P5\n%ld %ld\n%d\n",

	    (long) cinfo->output_width, (long) cinfo->output_height,

	    PPM_MAXVAL);

    break;

  case JCS_RGB:

    /* emit header for raw PPM format */

    fprintf(dest->pub.output_file, "P6\n%ld %ld\n%d\n",

	    (long) cinfo->output_width, (long) cinfo->output_height,

	    PPM_MAXVAL);

    break;

  default:

    ERREXIT(cinfo, JERR_PPM_COLORSPACE);

  }

}





/*

 * Finish up at the end of the file.

 */



METHODDEF void

finish_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)

{

  /* Make sure we wrote the output file OK */

  fflush(dinfo->output_file);

  if (ferror(dinfo->output_file))

    ERREXIT(cinfo, JERR_FILE_WRITE);

}





/*

 * The module selection routine for PPM format output.

 */



GLOBAL djpeg_dest_ptr

jinit_write_ppm (j_decompress_ptr cinfo)

{

  ppm_dest_ptr dest;



  /* Create module interface object, fill in method pointers */

  dest = (ppm_dest_ptr)

      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,

				  SIZEOF(ppm_dest_struct));

  dest->pub.start_output = start_output_ppm;

  dest->pub.finish_output = finish_output_ppm;



  /* Calculate output image dimensions so we can allocate space */

  jpeg_calc_output_dimensions(cinfo);



  /* Create physical I/O buffer.  Note we make this near on a PC. */

  dest->samples_per_row = cinfo->output_width * cinfo->out_color_components;

  dest->buffer_width = dest->samples_per_row * (BYTESPERSAMPLE * SIZEOF(char));

  dest->iobuffer = (char *) (*cinfo->mem->alloc_small)

    ((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width);



  if (cinfo->quantize_colors || BITS_IN_JSAMPLE != 8 ||

      SIZEOF(JSAMPLE) != SIZEOF(char)) {

    /* When quantizing, we need an output buffer for colormap indexes

     * that's separate from the physical I/O buffer.  We also need a

     * separate buffer if pixel format translation must take place.

     */

    dest->pub.buffer = (*cinfo->mem->alloc_sarray)

      ((j_common_ptr) cinfo, JPOOL_IMAGE,

       cinfo->output_width * cinfo->output_components, (JDIMENSION) 1);

    dest->pub.buffer_height = 1;

    if (! cinfo->quantize_colors)

      dest->pub.put_pixel_rows = copy_pixel_rows;

    else if (cinfo->out_color_space == JCS_GRAYSCALE)

      dest->pub.put_pixel_rows = put_demapped_gray;

    else

      dest->pub.put_pixel_rows = put_demapped_rgb;

  } else {

    /* We will fwrite() directly from decompressor output buffer. */

    /* Synthesize a JSAMPARRAY pointer structure */

    /* Cast here implies near->far pointer conversion on PCs */

    dest->pixrow = (JSAMPROW) dest->iobuffer;

    dest->pub.buffer = & dest->pixrow;

    dest->pub.buffer_height = 1;

    dest->pub.put_pixel_rows = put_pixel_rows;

  }



  return (djpeg_dest_ptr) dest;

}



#endif /* PPM_SUPPORTED */

